This invention relates to air cell dunnage and, more particularly, to air cell dunnage which is intended to be inflated at the time of use.
Air cell dunnage is typically used for shipping products which may be subject to breakage. The dunnage may be wrapped around the product or stuffed into a container to prevent movement of the product within the container during shipment and to protect against shock.
Conventionally, manufacturing air cell dunnage involves vacuum forming a multiplicity of bubbles to form a bubble layer. The bubbles are separated by flats which are bonded (thermally) to a flat base layer to form a bubble sheet in which air is trapped within the hemispherical vacuum formed bubble. This bubble sheet or air cell dunnage as it is commonly known, is shipped in this form to end users who use the dunnage to package their products for shipment.
The manufactured bubble sheet is relatively bulky, being close to 100 times the thickness of the combined thickness of the plastic film from which the bubble sheet is manufactured. Obviously, this bulk increases the cost of shipping of the manufactured air cell dunnage to the ultimate end user.
Moreover, the manufacture of the bubble sheet takes place at relatively high temperature (for example, about 120xc2x0 C.). After the base layer is fused to the bubble layer, the temperature of the bubble sheet drops to room temperature which is approximately 20xc2x0 C. Because of this drop in temperature, the volume of the air within the individual bubbles or cells decreases by about 25%. Using these figures, this would mean that only about 75% of the available volume of a bubble is being used. It can be shown that when 75% of the available volume of a bubble is used, the height of the bubble is only 56% of the height of a fully inflated bubble. This means that if the individual bubbles could be expanded to their full size, the bulkiness (thickness) of the product would be almost doubled. Conversely, to achieve the bulkiness of a prior art bubble sheet in which the bubbles are only expanded to 75% of their volume, a fully expanded bubble sheet would require 44% less raw material. Thus, it is desirable to increase the percentage of the available volume of the bubbles which is filled with air.
The main object of this invention is to provide air cell dunnage which can be inflated by the end user, which means that the manufactured product is much less bulky than before and which also enables the individual bubbles to be filled with a greater volume of air.
A further object of the invention is to provide air cell dunnage in which less material is required for a specified amount of bulkiness.
In accordance with the invention, the individual cells of a bubble sheet are interconnected by a series of conduits which lead to atmosphere. When the bubble layer is fused to the base layer, the conduits function as a vent so that the fused bubble sheet can be flattened to evacuate the air within the bubble sheet. The flattened bubble sheet is shipped to the end user.
The end user inflates the bubble sheets by connecting the conduits to an air supply. This will take place at room temperature which means that the individual cells or bubbles can be completely filled with air. After the bubble sheet has been inflated, the individual conduit(s) are sealed so that the captured air is retained within the bubble sheet which can then be used in conventional fashion.